The LM3875 has 120 dB supply noise rejection. According to my measurement with RMAA and soundcard, inverting gainklone has 82 dB S/N ratio, so regulating supply voltages does not make sense, as long as there is enough voltage to drive the speakers.

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Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?

I am kind of confused on the grounding scheme. I understand the need for both star and power grounds. In the schematics, the power ground is connected to the DC 0V "G" which is correct.

Do I need to connect the Power Ground (PG) to "Earth" (the mains earth wire). In the beginners guide, it mentioned that we should connect the PG to earth via a 100 Ohm resistor and a 0.22microf capacitor. Why do we need that?